1. Field of the Invention
This invention relates to an apparatus for removing branches from and for crosscutting treetrunks, which apparatus comprises a frame, which is adapted to be suspended from a lifting tackle and is provided with grippers for engaging the treetrunk from below, with a longitudinal feeding device for moving the treetrunk in its longitudinal direction, with branch-removing tools, which are spaced around the treetrunk, and with a crosscutting tool, which is movable transversely to the direction of the longitudinal feed movement and preferably consists of a circular saw.
2. Description of the Prior Art
Such apparatuses for removing branches are carried by a suitable lifting tackle, which in most cases consists of a crane that is mounted on a separate chassis. The apparatuses for removing branches can skilfully be manipulated when they are suspended from the lifting tackle. When it is desired to remove branches from the treetrunks the apparatus is lowered onto the felled tree with the grippers open. Thereafter the grippers engage the treetrunk from below and hold and guide the treetrunk for the continued processing. When the apparatus which has been coupled to the treetrunk has been lifted the feeding device moves the treetrunk in its longitudinal direction past the branch-removing knives, which face in the opposite direction and which may be secured to separate knife carriers or directly to the gripper arms. Branches are removed from the treetrunk all around its periphery as the treetrunk is pulled through the apparatus. When all branches have been removed from the treetrunk it may be cut to a desired length by a suitable crosscutting device so that felled trees can be stored in an efficient manner.
In dependence on the tool arrangement, the ranges in which the gripper can engage the treetrunk, the feeding power and, above all, the cutting conditions of the crosscutting tool, said apparatuses for removing branches and for cutting to length are designed for processing treetrunks having a certain maximum dimension, which is particularly determined by the crosscutting tool because the structural design will limit the cutting depth and the cutting range of the crosscutting tool. Whereas a circular saw owing to its fast and reliable operation is a suitable crosscutting tool, the maximum size of treetrunks to be processed will necessarily depend on the radius of the circular sawblade so that the range of use will be considerably restricted. It must also be taken onto account that most treetrunks have a larger thickness at their lower end, where they merge into the rootstock so that an efficient processing of numerous treetrunks has not been possible thus far because that base portion is oversize. This is due to the fact that a design of the branch-removing and crosscutting apparatus for an accommodation of that thicker portion would involve an intolerable additional expenditure and because apparatuses having suitable dimensions could not be used on such thicker portions. For this reason it has been necessary in practice to cut off excessively thick treetrunk sections by means of separate chain saws or by suitable handtools so that the treetrunks had to be prepared by hand for a subsequent further processing of the treetrunks by a machine. That prior manual work is complicated and difficult and involves a high labor expenditure and a high accident risk.